As early autumn starts to twirl around the garden, there are still pockets of space to be found for fast and furious greens that will pepper salads; with care and a little protection, these will grow plentiful enough to cook with.
Mizuna, the fastest-growing of the Asian greens, is the easiest of the lot – and a good starting point if you are new to these delicious vegetables. Then there’s mibuna, which has rounder leaves than mizuna, but with a similar taste – mildly spicy and grassy. Tsoi sim is grown for its edible flower shoots and leaves, and can be ready to pick in four weeks. Finally, there are frilly mustards (a cross between mustard and kale): golden frills, red frills and purple frills, which look more like seaweed than vegetables grown on land, but all that fine-leaf filigree means it never gets too spicy. These greens are so exuberant they race to grow as soon as the seed hits the ground.
If the weather is kind, succession-sow until the middle of the month. By October, the light levels will be too low for any decent growth and even if the seed germinates, it will be too weak to get going and be mown down by slugs.
The one thing you must do is offer these greens protection as autumn progresses. That might mean a greenhouse or polytunnel, growing under a cloche (clear storage boxes work well) or fleece, because once the nights grow colder, you need to keep the leaves tender or the flavour will be too mustardy.
There are several ways to sow. They are relatively shallow-rooted, so you could use window boxes or five-litre pots and containers to grow them as baby leaves. They will reach about 10-15cm high, so you might make two or three cuts before the plant cottons on to your tricks and gets too tough to eat raw. If you go for this method, scatter the seed so there is 5-10cm between each one. If this sounds a little too precise, scatter liberally and thin to the right distance. If you use scissors to thin out the seedlings, use the spoils as a sprinkling of microgreens on a supper dish. If you yank them up, you will curse trying to get soil off the tiny roots.
The other option is to sow straight into the ground or into modules to plant out in a couple of weeks. Choose a sunny spot – these greens need good light to grow well. If the weather is in the least bit cool, cover with fleece to aid germination. If you sow in modules, plant out the plugs once the tomatoes or cucumbers are finished in greenhouses or polytunnels.
https://www.theguardian.com/lifeandstyle/2021/sep/04/how-to-sow-fast-growing-greens